Presence Verification

Presence inspection is used to confirm the quantity or the presence/absence of parts or components on a target. There is a considerable variety of presence inspection used in machine vision. For example:

Verification of clips, screws, springs, components and parts in place

Counting components in pallets

Verifying the presence of products in packages

Monitoring the appearance of labels, marks, print and seals

Confirming the presence of electronic components on PCBs

Proving the existence of screws/washers for securing parts

Verifying the presence of adhesive beads

Type verification for Just-In-Time build manufacturing

Monitoring the occurrence of cuts in material

Industry 4.0 flexible manufacturing checks

Presence inspection vision solutions by IVS® are used on automated production lines for quality control. Due to increased factory automation, industrial vision systems and image processing technologies have been actively introduced into industrial automation over the last few years. Here we describe the advantages of using vision systems and machine vision for presence verification inspection, combined with the basic principle and practical applications of presence inspection using image processing.

Presence inspection has depended on visual inspection using human operators for many years. However, this involved the risk of missing failures depending on the physical condition or experience of inspectors, the light in the room or the time of day of inspection. Machine vision has been introduced to reduce human errors and improve work efficiency for inspection tasks involving presence verification.

Manual visual inspection causes variations in accuracy due to individual differences among operators and missed quality criteria. 100% quality inspection requires a large amount of time and effort on the part of the manufacturer. To solve these problems, IVS machine vision has been introduced to replace human eyes for recognising and judging presence targets. In recent years, HD full-colour cameras capable of high-speed transfer have become available, and image processing technology has also seen significant advances. IVS machine vision is now widespread in industrial automation.

There are a number of ways the IVS vision system can complete presence verification; these include:

Threshold-based analysis

Pattern-based “target” verification using a master template

Contour-based verification

Colour image processing

Threshold-based analysis: Binary processing converts the image represented in greyscale into an image that consists of two levels, black or white. Each pixel is changed into black or white based on a specified threshold level. This is the traditional way of presence verification in machine vision.

Template matching: A master “template” is trained for the part or component requiring verification. Every image is then compared against the master for matching verification.
Contour-based verification: IVS system can use geometric features to find an object. We can quickly and reliably find multiple models that are translated, rotated, and scaled with sub-pixel accuracy. The system locates an object that is partially missing and continues to perform when a scene is subject to uneven changes in illumination, thus reducing lighting requirements.

Colour-based checking: Using 24-bit RGB analysis of an area allows specific coloured components to be easily identified in a scene.

Fully automated vision control enables IVS customers to deliver a superior and quality product. Vision can be used as part of the manufacturing or packaging line quality control to confirm final products, components or packs are verified as complete and good for sale. Check sub-assemblies are complete and to customer specifications.

To verify parts, assemblies and packaged goods, our vision systems provide high speed, reliable options for checking the presence, size, position, shape and completeness of features. Machine vision systems are also used to check assemblies, sub-assemblies and components are complete and meet customer specifications and to automatically identify defects before parts leave the the production line allowing yields to increase and ppm counts to fall.

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